uvm_fault(0xffffffff83a99f70, 0xffff800029c621a0, 0, 1) -> d
kernel: page fault trap, code=0
Stopped at      ffs2_balloc+0xa0a:      movq    0(%rcx,%rax,8),%r14
    TID    PID    UID     PRFLAGS     PFLAGS  CPU  COMMAND
ffs2_balloc(fffffd806c937500,100700,40,fffffd8007ffd548,1,ffff80003c907828) at ffs2_balloc+0xa0a sys/ufs/ffs/ffs_balloc.c:614
ffs_write(ffff80003c9078b0) at ffs_write+0x4f9 sys/ufs/ffs/ffs_vnops.c:345
VOP_WRITE(fffffd807a7e4da8,ffff80003c907948,23,fffffd8007ffd548) at VOP_WRITE+0x101 sys/kern/vfs_vops.c:245
vn_rdwr(1,fffffd807a7e4da8,ffff80003c907a80,40,0,1,dfba79eb6b08fe37,0,1008,40) at vn_rdwr+0x12d sys/kern/vfs_vnops.c:330
acct_process(ffff80003c8fb778) at acct_process+0x7a2 sys/kern/kern_acct.c:245
exit1(ffff80003c8fb778,0,0,1) at exit1+0x5c4 sys/kern/kern_exit.c:228
sys_exit(ffff80003c8fb778,ffff80003c907cb0,ffff80003c907c00) at sys_exit+0x1a sys/kern/kern_exit.c:-1
syscall(ffff80003c907cb0) at syscall+0x962 mi_syscall sys/sys/syscall_mi.h:-1 [inline]
syscall(ffff80003c907cb0) at syscall+0x962 sys/arch/amd64/amd64/trap.c:783
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x79257d6a1ef0, count: 6
https://www.openbsd.org/ddb.html describes the minimum info required in bug
reports.  Insufficient info makes it difficult to find and fix bugs.
ddb> 
ddb> set $lines = 0
ddb> set $maxwidth = 0
ddb> show panic
*cpu0: uvm_fault(0xffffffff83a99f70, 0xffff800029c621a0, 0, 1) -> d
ddb> trace
ffs2_balloc(fffffd806c937500,100700,40,fffffd8007ffd548,1,ffff80003c907828) at ffs2_balloc+0xa0a sys/ufs/ffs/ffs_balloc.c:614
ffs_write(ffff80003c9078b0) at ffs_write+0x4f9 sys/ufs/ffs/ffs_vnops.c:345
VOP_WRITE(fffffd807a7e4da8,ffff80003c907948,23,fffffd8007ffd548) at VOP_WRITE+0x101 sys/kern/vfs_vops.c:245
vn_rdwr(1,fffffd807a7e4da8,ffff80003c907a80,40,0,1,dfba79eb6b08fe37,0,1008,40) at vn_rdwr+0x12d sys/kern/vfs_vnops.c:330
acct_process(ffff80003c8fb778) at acct_process+0x7a2 sys/kern/kern_acct.c:245
exit1(ffff80003c8fb778,0,0,1) at exit1+0x5c4 sys/kern/kern_exit.c:228
sys_exit(ffff80003c8fb778,ffff80003c907cb0,ffff80003c907c00) at sys_exit+0x1a sys/kern/kern_exit.c:-1
syscall(ffff80003c907cb0) at syscall+0x962 mi_syscall sys/sys/syscall_mi.h:-1 [inline]
syscall(ffff80003c907cb0) at syscall+0x962 sys/arch/amd64/amd64/trap.c:783
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x79257d6a1ef0, count: -9
ddb> show registers
rdi                                0
rsi                                0
rbp               0xffff80003c9077d0
rbx               0xfffffd806c937500
rdx                                0
rcx               0xffff800029c62000
rax                             0x34
r8                0xffffffffffffffff
r9                0xffff80003c907828
r10               0xc0886a35ae03754b
r11               0xb313548f1da0b785
r12                              0x1
r13               0xffff800000c47800
r14               0xffff80003c907670
r15               0xfffffd805c773e78
rip               0xffffffff8155d14a    ffs2_balloc+0xa0a
cs                               0x8
rflags                       0x10246    __ALIGN_SIZE+0xf246
rsp               0xffff80003c907660
ss                              0x10
ffs2_balloc+0xa0a:      movq    0(%rcx,%rax,8),%r14
ddb> show proc
PROC (syz-executor) tid=634 pid=30613 tcnt=0 stat=onproc
    flags process=1008<EXITING,SINGLEEXIT> proc=2000<WEXIT>
    runpri=86, usrpri=86, slppri=32, nice=20
    wchan=0x0, wmesg=, ps_single=0xffff80003c8fb778 scnt=-1 ecnt=1
    forw=0xffffffffffffffff, list=0xffff80003c8fa020,0xffff80003c8fba20
    process=0xffff80003c9816a0 user=0xffff80003c902000, vmspace=0xfffffd806cae5740
    estcpu=36, cpticks=5, pctcpu=0.0, user=0, sys=1, intr=0
ddb>